Field of the Invention
The present invention relates to an engine control system with a variable turbocharger, and a method thereof. More particularly, the present invention relates to an engine control system with a variable turbocharger and a method thereof in which an operation region is divided into a steady-speed driving region, an acceleration driving region, and a deceleration driving region, and in which the variable turbocharger and an engine are controlled according to the operation region.
Description of Related Art
As is known in the art, when air at a higher pressure than atmospheric pressure is charged into an engine, a large amount of air can be supplied thereto. In addition, output power of the engine is increased when an amount of injected fuel is increased.
A turbocharger that turbocharges air to the engine is used. The turbocharger rotates a turbine using exhaust gas, and a blower connected thereto through a shaft is rotated. Therefore, the turbocharger compresses external air and supplies the compressed air to a cylinder of the engine.
FIG. 1 is a perspective view illustrating a general turbocharger, and FIG. 2A and FIG. 2B are schematic views illustrating a general turbocharger.
As shown in FIG. 1, the general turbocharger 100 is one in which a flow passage area of exhaust gas is varied according to a variation of a vane angle. Therefore, output power of an engine 200 is changed. This type of turbocharger is called a variable turbocharger (VGT: variable geometry turbocharger). The turbocharger includes a turbine 122 rotated by exhaust gas exhausted by the engine 200, and a compressor 110 that is rotated in synchronization with the turbine 122 and that compresses external air and supplies the compressed air to a cylinder.
A vane is provided in a turbine housing 120. The vane 130 varies a flow passage area of exhaust gas according to an operation region of the engine such that output power of the engine is controlled. That is, the operation region of the engine is divided into a high-speed region and a low-speed region, and output power of the engine is controlled by adjusting an opening of the vane.
However, according to the conventional art, the turbocharger is operated in the operation region of the engine (high-speed region or low-speed region) such that there is a problem that control is not performed considering a steady-speed driving region, an acceleration driving region, or a deceleration driving region.
Further, according to the conventional art, it is possible to control an air-fuel ratio by increasing a boost pressure in a normal condition of the engine. However, since required boost pressure is not instantaneously formed because of turbo-lag in the acceleration driving region, there is a problem that the air-fuel ratio is not fluently controlled.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.